In a recent study, the incidence of pancreatic carcinomas in carcinogen-treated rats and hamsters was lowered by feeding a mixture containing glyceryl monooleate and propylene glycol. This outcome could reflect and effect of absorbed glyceryl monooleate or propylene glycol, or could be due to altered absorption of another dietary factor in chow that inhibits pancreatic carcinogenesis. Additional background data favors the latter over the former mechanism. This project will compare the effect of these two compounds on the incidence of pancreatic carcinomas in azaserine-treated rats when they are added to chow and to purified diets. The incidence of pancreatic carcinoma will also be evaluated in groups of rats fed diets to which glyceryl monooleate and propylene glycol are added separately. Finally, the effect of these dietary additives on the incidence of carcinoma in an experimental model of breast carcinogenesis will be evaluated. The long range goal is to elucidate the mechanism of inhibition of carcinogenesis by glyceryl monooleate and/or propylene glycol, and to determine which component is responsible for inhibition of carcinogenesis.